Dimmer switch



Aug. 25, 1925.

DIMMER SWITCH Filed Sept. B. 1922 ao: Hug

Patented Aug. 25, 1925.

UNITED STATES ALEX MCDOUGALL, OF COLUMBIA, SOUTH CAROLINA.

DIMMER SWITCH.

Application filed September 8, 1922.

T o all whom it may concern:

Be it known that I, ALEX MoDoUGALL, a citizen of the United States, residing at Columbia, in the county of Richland and State of South Carolina, have invented certain new and useful Improvements in Dimmer Switches, of which the following is a specification.

This invention relates to switches of the push button type, and especially to switches for controlling the amount of resistance in a circuit.

Although the invention is capable of a number of different uses, it has been especially designed for use as a dimmer switch for automobile headlights. As is well known, it is desirable, when approaching a car moving in the opposite direction, or on other occasions, to soften or dim the brilliancy of the headlights, and the object of the present invention is to provide a simple, compact, convenient and self-contained device by means of which this dimming can be readily accomp-lished with the least possible efort on the part of the operator.

In order that the invention may be readily understood reference is had to the accompanying drawing forming part of this specification, and in which:

Fig. 1 is a vertical section through my improved dimmer switch, complete;

Fig. 2 is a sectional plan, substantially on the line 9.-2 of Fig. l;

Fig. 3 is a side elevation of the complete switch;

Fig. 4 is a side elevationvof the interior pats of the switch, with the casing removed; an

Fig. 5 is a diagram illustrating the circuit connections for the switch.

Referring to the drawings in detail, my improved push button switch comprises a cylindrical metallic casing 1, open at both ends, and having a flange 2 at one end by means of which it may be mounted upon and secured to a suitable support. Inside of the casing 1 is tted a body or block 3 of insulating material. This is insertable through the open lower end of the casing, and its upper edge is received under an annular shoulder 1b formed on the interior wall of the casing. In this way, when the parts are assembled, the block 3 is securely held in position.

Formed in the block 3 is an annular groove 4, and in this groove l is wound a suitable serial No. 586,979.

quantity of resistance wire 5. This may be insulated with enamel, asbestos, or other suitable material. The two ends of the coil 5 of resistance wire are electrically connected to two combination binding posts and contacts 6 which may be mounted in the block 3 and extend vertically therethrough. The upper ends of these binding posts are enlarged to form contacts 7 and each such contact carries an inwardly projecting lip or lug 7a at its eXtreme upper end.

Adapted to form an electrical connection between the contacts 7 is a bridge plate 8 carried by a plunger 9, the plate and plunger being normally held up in contact with the under side of the lugs 7 l by means of a spring 10 which surrounds the lower part of the plunger below the plate and is received in a suitable recess formed in the center of the block 3. Thus the bridge plate 8 is normally in engagement with the contacts 7 and when in such position serves to short circuit the resistance wire 5.

In order to depress the plate 8 and move it out of engagement with the contact lugs 7a, I provide a push button 11, preferably made of insulating material and fitted into the upper end of the casing 1. This push button has at its under side a socket fitting over the top of plunger 9, and is provided around its edge with a peripheral flange 11a adapted to enga-ge under an inturned marginal flange 1Z1 formed on the casing. It will be understood that the block 3 terminates a suflicient distance below the top of the casing to provide a space in which the push button 11 can reciprocate, and it will also be understood that a sufficient clearance is provided between the side faces of the contacts 7 and the bridge plate 8 to prevent such plate from engaging such side faces at the same time. Thus, when the push button 11 is depressed, the bridge plate 8 is caused to move downwardly and thus shifted out of contact with the .lugs 7a, thereby breaking the short-circuit, and throwing the resistance wire into circuit between the two binding posts.

The lower face of the block 3 is cut away to provide a recess 12 into which the lower ends of the binding posts 6 extend, such ends being provided with suitable nuts 13 by means of which wires extending to the circuit to be controlled can be attached to the binding posts. In order that these wires may be readily led to the outside circuit,

tl t) an opening 14 in the block o is provided and this is arranged to register with a similar opening formed in the casing l as clearly shown in Fig. 3. The circuitwires extending from the battery to the lamps are led through these openings.

By reference to Fig. 5, the manner of connecting my improved dimmer switch in the ordinary lamp circuit of a motor vehicle will be readily understood. In this ligure, the usual battery is indicated at- B and the headlights at L, one side of both battery and lights being grounded. From the other side of the battery extends a wire a to one ot the binding posts ot my improved switch, and from the other binding post eittends a wire to the lamps, the usual dashboard switch S being included in this circuit. As above stated the resistance wire 5 is permanently connected to the two binding posts 6 of my improved switch.

From the above it will be understood that normally the bridge plate 8 is in engagementwith the contacts Y, thus short-circuiting the resistance 5 and enablingthe lamps to burn at full candle power. lWhen it is desired to dim the lamps, the operator simply depresses the button ll thus ren'loving the bridge plate 8 from lthe contacts T and thereby inserting the resistaiice 5 in the circuit c., b.

litty .improved switch may be either mounted on the floor so as to be engaged by the Ytoot oit lthe operator, or it may be mounted on the side o't the car so as to be engaged by his linee, or in any other suitable place.

that l claim is:

l. A resistance controlling switch comprising a. cylindrical casing, open at both ends, one end oft said casing having an outwardly extending annular radial flange adapted to be secured against a flat surface, and the other end ot said casing having an inwardly extending annular flange, a push button movably mounted in and closing said last mentioned end of the casing, and limited in its outward movement by said inwardly extending flange, a circuit closer arranged to be operated by said push button, said circuit closer comprising a pair of spaced contacts and a bridging member, and a resistance. coil having its ends connected with said contacts, said coil and contacts lying wholly within said casing and bodily removable therefrom as a suit.

2. A, resistance controlling switch comprising a cylindrical casing open at its ends, a block ot' insulating material insertable into said casing from one end, said blocl; having an annular groove and a central recess formed therein, a resistance wire wound in said groove, a push button movably mounted in the other end of said casing, a spring seated in said recess and supporting said push button and means within said casing, and controlled by said push button, tor short circ-uiting said resistance wireu 8. A resistance controlling switch comprising a cylindrical casing open at its ends, a block of' insulating material in said casing, said block having an annular groove formed therein, a resistance wire wound in said groove, a push button movably mounted in and closing one end of said casing, a circuit closer Comprising a pair of combined contacts and binding posts and a bridge plate, said combined contacts and binding posts being connected with the ends ot said resistance wire and adapted to be also connected with the circuit to be controlled, a spring tending to move said bridge plate in one direction, and said push button serving to move it in the opposite direction, said circuit closer in its entirety, including the spring, being carried by said block of insulating material, and all of said parts being insertable and removable as a unit into and it'roin 'the end of the casing opposite that in which the push button is mounted.

ln testimony whereof I aflix my signature.

ALEX MCDOUGALL. 

